Irradiated multilayer film for primal meat packaging

ABSTRACT

A heat-shrinkable, multilayer film suitable for use in fabricating bags for packaging primal and sub-primal meat cuts and processed meats. The multilayer film has a first outer layer of an ethylene-vinyl acetate copolymer, a core layer of a barrier film comprising vinylidene chloride-methyl acrylate copolymer, and a second outer layer of an ethylene-vinyl acetate copolymer. The multilayer film is preferably made by co-extrusion of the layers, and then it is biaxially stretched. After biaxial stretching, the multilayer film is irradiated to a dosage level of between 1 megarad and 5 megarads and heat-sealed in the form of a bag. The bag has improved storage stability characteristics.

FIELD OF THE INVENTION

This invention relates to an irradiated multilayer film suitable for usein the manufacture of bags for packaging primal and sub-primal meat cutsand processed meats. This invention also relates to such film comprisingan irradiated three-layer film wherein the outer layers of the filmcomprise ethylene-vinyl acetate copolymers, and the core layer comprisescopolymers of vinylidene chloride and methyl acrylate, and to theprocess for manufacturing such film.

BACKGROUND OF THE INVENTION

Primal meat cuts, or primals, are large cuts of meat, smaller, forexample, than a side of beef, but larger than the ultimate cut that issold at retail to the consumer. Primal cuts are prepared at theslaughter house and are then shipped to a retail meat store or aninstitution such as a restaurant where they are butchered into smallercuts of meat called sub-primal meat cuts or sub-primals. Sub-primals mayalso be prepared at the slaughter house. When primals and sub-primalsare prepared at the slaughter house, they are usually packaged in such away that air (i.e., oxygen) is prevented from contacting the meat duringshipping and handling in order to minimize spoilage and discoloration.One desirable way to package primals and sub-primals so as to protectthem from degradation due to moisture loss and contact with air is toshrink package them with a packaging material that has good barrierproperties. One such shrink packaging material that has good oxygen andmoisture barrier properties is vinylidene chloride-vinyl chloridecopolymer film.

One approach to the provision of a film for use in shrink packagingprimal and sub-primal meat cuts and processed meats is to employ amultilayer film having oxygen and moisture barrier properties, one layerof which is a vinylidene chloride-vinyl chloride copolymer film. Theother layer or layers of such a multilayer film are selected so as toprovide the requisite low temperature properties and abrasion resistancewhich are lacking in vinylidene chloride-vinyl chloride film. Inproviding such a film, however, it must be recognized that good barrierproperties, abrasion resistance, and low temperature properties are notthe only requirements for a film that is to be used for shrink packagingprimal and sub-primal meat cuts. The film must have been biaxiallystretched in order to produce shrinkage characteristics sufficient toenable the film to heat shrink within a specified range of percentages,e.g., from about 30 to 60 percent at about 90° C., in both the machineand the transverse directions.

The film must also be heat sealable in order to be able to fabricatebags from the film and in order to heat seal the open mouths of thefabricated bags when the meat cut has been placed within the bag.Additionally, the heat sealed seams of the bags must not pull apartduring the heat shrinking operation, the film must resist puncturing bysharp edges such as bone edges during the heat shrinking operation, andthere must be adequate adhesion between the several layers of the filmso that delamination does not occur, either during the heat shrinkingoperation or during exposure of the film to the relatively hightemperatures that may be reached during shipping and storage of the filmin the summertime.

It has been proposed to prepare multilayer films, one layer of which isa vinylidene chloride-vinyl chloride copolymer and at least one otherlayer of which is an ethylene-vinyl acetate copolymer. For example, suchfilms are proposed in McFedries, Jr., et al. U.S. Pat. No. 3,600,267,Peterson U.S. Pat. No. 3,524,795, Titchenal et al. U.S. Pat. No.3,625,348, Schirmer U.S. Pat. Nos. 3,567,539 and 3,607,505, and Widigeret al. U.S. Pat. No. 4,247,584.

In addition, multilayer films comprising a core layer of a vinylidenechloride copolymer, wherein the vinylidene chloride copolymer is acopolymer of a vinylidene chloride monomer and a vinyl chloride monomer,are known, for example as disclosed in Brax et al, U.S. Pat. Nos.3,741,253 and 4,278,738, Baird et al, U.S. Pat. No. 4,112,181, andLustig et al. Canadian Pat. No. 982,983.

Also in the prior art, cross-linking by irradiation has been used toenhance the properties of films employed in packaging operations. Forexample, U.S. Pat. No. 3,741,253 to Brax et al. teaches a multi-plylaminate having a first ply of ethylene-vinyl acetate which iscross-linked by irradiation. The second ply and the third ply of thelaminate are not irradiated. The thus-prepared laminate may then bebiaxially stretched. Baird et al. U.S. Pat. Nos. 3,821,182 and 4,112,181teach a three-layer film combination which has been irradiated beforestretching. Further, Bernstein et al. U.S. Pat. Nos. 4,391,862 and4,352,844 disclose co-extruding first and second polymeric layers,irradiating the co-extruded layers, joining a third layer to the secondpolymeric layer, and then stretching the multilayer film. Still further,Bieler et al. U.S. Pat. No. 4,318,763 teaches that the seals of the bagsmade of multilayer film may be strengthened by cross-linking the sealarea of the bag by irradiation.

However, it has been found that an irradiated multilayer film containinga vinylidene chloride-vinyl chloride copolymer layer discolorssignificantly during storage due to degradation of the vinylidenechloride-vinyl chloride layer. It is believed that discoloration of thevinylidene chloride-vinyl chloride copolymer layer is due to radiationinduced cleavage of hydrogen and chloride radicals therein, therebyresulting in the production of double bonds and the associatedchromophores.

The present invention is based upon the discovery that multilayer films,fully described below, having outer layers of ethylene-vinyl acetatecopolymers and having a core layer of a vinylidene chloride-methylacrylate copolymer barrier film, which are irradiated after biaxialstretching to cross-link the ethylene-vinyl acetate layers, can besuccessfully employed in the shrink packaging of primal and sub-primalmeat cuts and processed meats. Specifically, this invention providessuch a multilayer film that has outstanding color stability afterirradiation, whereby it can be advantageously employed to fabricate bagsuseful for shrink packaging primal and sub-primal meat cuts andprocessed meats.

SUMMARY OF THE INVENTION

Pursuant to the instant invention, it has been found that aheat-shrinkable multilayer film having outer layers of ethylene-vinylacetate copolymers and a core layer of a vinylidene chloride-methylacrylate copolymer barrier film, wherein the multilayer film has beenbiaxially stretched and then irradiated to a dosage level of betweenabout 1 megarad and about 5 megarads, when employed to make bags forpackaging primal and sub-primal meat cuts and processed meats, such afilm provides bags having improved physical characteristics, whereby thebags when stored are more color-stable than those of the prior art andhave the ability to withstand high sealing temperatures.

BRIEF DESCRIPTION OF THE DRAWING

FIG. 1 is a graphic representation of color development in irradiatedfilms after various storage periods.

DETAILED DESCRIPTION OF THE INVENTION

In accordance with this invention, there is provided a heat shrinkablemultilayer film having a first outer layer comprising a firstethylene-vinyl acetate copolymer, said first ethylene-vinyl acetatecopolymer having a melt index of from about 0.1 to about 1.0 decigramper minute and a vinyl acetate content of from about 9 to about 15weight percent, based on the weight of said first ethylene-vinyl acetatecopolymer; a core layer comprising a vinylidene chloride-methyl acrylatecopolymer containing from about 5 weight percent to about 15 weightpercent methyl acrylate, based on the weight of said copolymer; and asecond outer layer comprising a second ethylene-vinyl acetate copolymerselected from the group consisting of (a) an ethylene-vinyl acetatecopolymer having a melt index of from about 0.1 to about 1.0 decigramper minute and a vinyl acetate content of from about 3 to about 18weight percent, and preferably from about 10 to about 15 weight percent,based on the weight of said second ethylene-vinyl acetate copolymer, and(b) a blend of two ethylene-vinyl acetate copolymers, wherein one ofsaid ethylene-vinyl acetate copolymers has a melt index of from about0.1 to about 1.0 decigram per minute and a vinyl acetate content of fromabout 10 to 18 weight percent, based on the weight of said copolymer,and the other ethylene-vinyl acetate copolymer has a melt index of fromabout 0.1 to about 1.0 decigram per minute and a vinyl acetate contentof from about 2 to about 10 weight percent, based on the weight of saidcopolymer. The blend (b) of said two ethy1ene-viny1 acetate copolymershas a vinyl acetate content of from about 3 to about 18 weight percent,and preferably from about 10 to about 15 weight percent, based on theweight of said copolymers. The first ethylene-vinyl acetate copolymercan be a single ethylene-vinyl acetate copolymer or a blend of at leasttwo ethylene-vinyl acetate copolymers having melt indices and vinylacetate contents within the aforementioned ranges.

The heat shrinkable multilayer film of this invention can be produced byknown techniques such as by co-extruding the multiple layers into aprimary tube, followed by biaxially stretching the tube by knowntechniques to form a heat shrinkable film. The "double bubble" techniquedisclosed in Pahlke U.S. Pat. No. 3,456,044, is suitable for use inproducing the film of this invention. After biaxial stretching, themultilayer film is then irradiated to a dosage level of between about 1megarad and about 5 megarads, such as by passing it through an electronbeam irradiation unit. The multilayer film may then be employed tomanufacture heat-shrinkable bags useful in packaging primal andsub-primal meat cuts and processed meats.

In accordance with a preferred embodiment of this invention, the firstouter layer of the multilayer film is an ethylene-vinyl acetatecopolymer containing from about 9 to about 15 weight percent of vinylacetate, based on the weight of the copolymer, said copolymer having amelt index of between about 0.1 and about 1.0 decigram per minute, andit may be selected from the group consisting of (a) a singleethylene-vinyl acetate copolymer and (b) a blend of ethylene-vinylacetate copolymers having melt indices and vinyl acetate contents withinthe aforementioned ranges of values.

Further, in a preferred embodiment of this invention the core layer ofthe multilayer film of this invention comprises a vinylidenechloride-methyl acrylate copolymer containing at least 85 weight percentof vinylidene chloride, based upon the weight of the vinylidene chloridecopolymer. The remainder of the vinylidene chloride copolymer is methylacrylate. More preferably, the vinylidene chloride-methyl acrylatecopolymer will contain at least about 85 weight percent, and not morethan about 95 weight percent, of polymerized vinylidene chloride becausewhen the vinylidene chloride copolymer contains less than about 85weight percent vinylidene chloride, the methyl acrylate content would begreater than the maximum amount approved by the Food and DrugAdministration for food contact uses, which is 15 percent by weight ofthe copolymer. If the vinylidene chloride content is more than 95 weightpercent, the vinylidene chloride copolymer is generally not extrudable.

The vinylidene chloride copolymer preferably contains less than 5 weightpercent plasticizer, the percentage being based on the total weight ofthe blend of copolymer and all additives including plasticizer, in orderto maximize the barrier properties of the thin film. Conventionalplasticizers such as dibutyl sebacate and epoxidized soybean oil can beused.

The second outer layer of the multilayer film of this inventioncomprises an ethylene-vinyl acetate copolymer selected from the groupconsisting of (a) an ethylene-vinyl acetate copolymer having a meltindex of from about 0.1 to about 1.0 decigram per minute and a vinylacetate content of from about 3 to about 18 weight percent, andpreferably from about 10 to about 15 weight percent, based on the weightof said second ethylene-vinyl acetate copolymer, and (b) a blend of twoethylene-vinyl acetate copolymers, wherein one of said ethylene-vinylacetate copolymers has a melt index of from about 0.1 to about 1.0decigram per minute and a vinyl acetate content of from about 10 toabout 18 weight percent, based on the weight of said copolymer, and theother ethylene-vinyl acetate copolymer has a melt index of from about0.1 to about 1.0 decigram per minute and a vinyl acetate content of fromabout 2 to about 10 weight percent, based on the weight of saidcopolymer. The blend (b) of said two ethylene-vinyl acetate copolymershas a vinyl acetate content of from about 3 to about 18 weight percent,and preferably from about 10 to about 15 weight percent, based on theweight of said copolymers.

The multilayer film of this invention will generally have a totalthickness of from about 1.75 mils to about 3.0 mils, and preferably offrom about 2.0 mils to about 3.0 mils, because when the thickness of themultilayer film is more than 3.0 mils, clipping problems are encounteredin that it is difficult to gather together the open end of a bag madetherefrom. When the thickness of the multilayer film is less than 1.75mils, the bag will have diminished puncture resistance. The first outerlayer will normally have a thickness of from about 1.1 mils to about 1.6mils; the core layer will normally have a thickness of from about 0.25mil to about 0.45 mil; and the second outer layer will normally have athickness of from about 0.4 mil to about 1.0 mil.

The thickness of the first outer layer, which is the inner layer of thebag, should be within the aforementioned range because the sealing andprocessability properties of the film layer would otherwise bediminished. The thickness of the core layer should be within theabove-indicated range because the film would provide inadequate barrierproperties if the core layer thickness is less than about 0.25 mil. Theupper limit of 0.45 mil for the core layer is primarily due to economicconsiderations. The thickness of the second outer layer, which is theouter layer of the bag, is selected in order to provide a totalthickness of the multilayer film in the range of from about 1.75 mils toabout 3.0 mils.

After biaxial stretching by any suitable method well known in the art,the multilayer film of this invention is irradiated to a dosage level ofbetween about 1 megarad and about 5 megarads, and preferably betweenabout 2 megarads and about 3 megarads, by any suitable method such as byemploying an electron beam. It has been found that the irradiationenergy applied to the multilayer film herein is important. That is, whenthe energy level is below the indicated range, sufficient cross-linkingis not obtained so as to improve the heat sealing characteristics of themultilayer film or to have any enhanced effect upon the toughnessproperties of the film. When the energy level is above theafore-mentioned range, film discoloration due to degradation of thepolyvinylidene chloride copolymer core layer is accelerated, the degreeof the film shrinkage is significantly reduced, and further improvementsin the heat sealing characteristics and toughness properties of the filmare not achieved.

In another aspect of this invention, bags suitable for the shrinkpackaging of primal and sub-primal meat cuts and processed meats areprovided from the afore-described multilayer film. The bags may beproduced from the three-layer film of this invention by heat sealing.For instance, if the film of this invention is produced in the form oftubular film, bags can be produced therefrom by heat sealing one end ofa length of the tubular film or by sealing both ends of the tube; thenslitting one edge to form the bag mouth. If the film of this inventionis made in the form of flat sheets, bags can be formed therefrom by heatsealing three edges of two superimposed sheets of film. When carryingout the heat sealing operation, the surfaces which are heat sealed toeach other to form seams are the said first outer layers of the films ofthe invention. Thus, for example, when forming a bag by heat sealing oneedge of a length of tubular film, the inner surface of the tube, i.e.,the surface which will be heat sealed to itself, will be the said firstouter layer of the film.

The invention is further illustrated by the examples which appear below.

In the examples, parts and percentages are by weight, unless otherwisespecified.

The following test methods were used in determining the properties ofthe resins and films used in the examples. Melt index values wereobtained pursuant to ASTM Method D-1238, condition E. Tensile strengthvalues were obtained following ASTM Method D-882, procedure A.

Non-ASTM test methods employed are described in the followingdiscussion. Shrinkage values were obtained by measuring unrestrainedshrink at 90° C. for five seconds.

The dynamic puncture-impact test procedure is used to compare films fortheir resistance to bone puncture. It measures the energy required topuncture a test sample with a sharp triangular metal point made tosimulate a sharp bone end. A Dynamic Ball Burst Tester, Model No. 13-8,available from Testing Machines, Inc., Amityville, Long Island, N.Y., isused and a 3/8 inch diameter triangular tip, as aforedescribed, isinstalled on the tester probe arm and employed in this test procedure.Six test specimens approximately 4 inches square are prepared, a sampleis placed in the sample holder, and the pendulum is released. Thepuncture energy reading is recorded. The test is repeated until 6samples have been evaluated. The results are calculated in cm-kg per milof film thickness.

The impulse sealing range test is run to determine the acceptablevoltage range for sealing a plastic film. A Sentinel Model 12-12ASlaboratory sealer manufactured by Packaging Industries Group, Inc.,Hyannis, MA was used. The sealing conditions were 0.5 second impulsetime, 2.2 seconds cooling time and 50 psi jaw pressure. The minimumvoltage was determined as that voltage which was capable of sealing fourpieces of film together, thereby simulating a fold commonly encounteredin field testing. The maximum sealing voltage was determined as thevoltage at which seal "burn-thru" begins to occur. "Burn-thru" isdefined as holes or tears in the seal caused by the high temperature andpressure of the sealing ribbon. "Burn-thru" has a detrimental effect onseal strength and package integrity, as well as final packageappearance.

EXAMPLE I

Biaxially stretched three-layer films were prepared by a "double bubble"process similar to that disclosed in U.S. Pat. No. 3,456,044 byco-extruding the following compositions through a multilayer die,biaxially stretching the co-extruded primary tube, and then irradiatingthe biaxially stretched tube.

Film composition 1 was made having an inner layer of ethylene-vinylacetate copolymer containing about 12 percent by weight of vinylacetate, based on the weight of the copolymer, and having a melt indexof about 0.25 decigram per minute (EVA Copolymer); a core layer ofvinylidene chloridevinyl chloride copolymer containing about 85 weightpercent vinylidene chloride and about 15 weight percent vinyl chloride(VDC-VC Copolymer); and an outer layer comprising a blend of (a) about75 weight percent of ethylene-vinyl acetate copolymer having about 12weight percent vinyl acetate and a melt index of about 0.35 decigram perminute, and (b) about 25 weight percent of ethylene-vinyl acetatecopolymer having about 4.5 weight percent vinyl acetate and a melt indexof about 0.25 decigram per minute (EVA Copolymer).

Film composition 2 had the same composition as film composition 1,except that the outer layer comprised an ethylene-vinyl acetatecopolymer having about 15 weight percent vinyl acetate and a melt indexof about 0.5 decigram per minute.

Film composition 3 had the same composition as film composition 1,except that the core layer comprised vinylidene chloride-methyl acrylatecopolymer containing about 8 weight percent methyl acrylate and having amolecular weight of about 100,000.

Film composition 4 had the same composition as film composition 1,except that the core layer comprised vinylidene chloride-methyl acrylatecopolymer containing about 8 weight percent methyl acrylate and having amolecular weight of about 115,000.

The resulting biaxially stretched films each had an average thickness ofabout 2.4 mils. The films were then each irradiated to a dosage level ofabout 3 megarads by passing the films through the electron curtain of anirradiation unit and immediately rewinding the films.

The physical properties of the irradiated films were evaluated and aresummarized in Table 1.

                                      TABLE 1                                     __________________________________________________________________________    Physical Properties of                                                        Irradiated Film Compositions                                                  Film            1     2     3     4                                           __________________________________________________________________________    Shrinkage @ 90° C., % MD/TD                                                            40/50 43/44 44/52 44/51                                       Tensile strength, psi, MD/TD                                                                  9400/9200                                                                           9900/9400                                                                           9800/9900                                                                           8500/8800                                   Elongation @ Break, % MD/TD                                                                   170/205                                                                             200/200                                                                             200/190                                                                             195/180                                     Dynamic Puncture, cmkg/mil                                                                    1.4   1.8   1.1   1.2                                         Oxygen Transmission,                                                                          1.4   1.4   1.25  1.62                                        (CC/100 in.sup.2 /24 hr./atm)                                                 __________________________________________________________________________     PG,17

It can be seen from Table 1 that the physical properties of filmcompositions 1 through 4 are similar.

The impulse sealing properties of film compositions 1, 3 and 4 werestudied and are summarized in Table 2. It can be seen therefrom that thesealing temperature is similar for the three film compositions. Thesealing device employed was a Sentinel Model 12-12AS, operated asearlier described.

                  TABLE 2                                                         ______________________________________                                        Sealing Properties of                                                         Irradiated Film Compositions                                                  Film          1            3     4                                            ______________________________________                                        Minimum voltage                                                                             27           26    26                                           Maximum voltage                                                                             40           40    40                                           ______________________________________                                    

The storage stability properties of film compositions 1 through 4 wereevaluated by placing samples thereof in an oven at a temperature ofabout 120° F. to simulate storage of up to 250 days at about 70° F. Thestorage stability properties of the film compositions were based uponthe color development of the film samples measured. The films werecompared to a set of color standards and given a numerical color rating.The rating system is as follows: 1--slight yellow cast, 2--moderateyellow cast, 3--unacceptable yellow color. The results of this study areshown graphically in FIG. 1 wherein the color rating measurements forfilm compositions 1 and 2 were combined, and those for film compositions3 and 4 were also combined. The color rating measurements for filmcompositions 1 and 2 are shown in FIG. 1 as the dotted line, and thosefor film compositions 3 and 4 are shown thereon as the solid line. Itcan be seen from FIG. 1 that film compositions 3 and 4, i.e., themultilayer films having a core layer of vinylidene chloride-methylacrylate copolymer, display far less color development than multilayerfilm compositions 1 and 2 having a core layer of vinylidenechloride-vinyl chloride copolymer. In addition, color development infilm compositions 3 and 4 leveled off after about the 120-day period,while film compositions 1 and 2 continued to discolor throughout thestudy period.

In summary, the novel film compositions of this invention have beenshown to possess physical properties required for use in packagingprimal and sub-primal meat cuts and processed meats, while additionallypossessing improved resistance to the color degradation caused byirradiation of the film. Furthermore, the film compositions of thepresent invention also have the required properties for use as bags,wherein the bags provide the desired heat-shrinking and heat-sealingcharacteristics in such packaging operations, while retaining a moredesirable appearance than those bags of the prior art.

In general, various conventional additives such as slip agents,antiblock agents, and pigments may be incorporated in the films of thepresent invention in accordance with conventional practice.

Although preferred embodiments of this invention have been described indetail, it is contemplated that modifications thereof may be made andsome preferred features may be employed without others, all within thespirit and scope of the invention. Additionally, although three-layerfilms are illustrated in the examples, multilayer films having less ormore than three layers are contemplated within the scope of thisinvention provided that at least one of the plurality of layerscomprises a layer of vinylidene chloride-methyl acrylate copolymer.

What is claimed is:
 1. a heat-shrinkable, biaxially stretched multilayerfilm suitable for packaging primal and sub-primal meat cuts andprocessed meats, said film containing a barrier layer comprising avinylidene chloride-methyl acrylate copolymer containing from about 5 toabout 15 weight percent of methyl acrylate, based on the weight of saidcopolymer.
 2. A heat-shrinkable, biaxially stretched multilayer film inaccordance with claim 1 wherein said barrier layer is a core layer.
 3. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 1 wherein said multilayer film has at least three layers.
 4. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 1 wherein said multilayer film has been irradiated to a dosagelevel of between about 1 megarad and about 5 megarads.
 5. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 1 wherein said film comprises a first outer layer comprising anethylene-vinyl acetate copolymer, a core layer comprising a vinylidenechloride-methyl acrylate copolymer, and a second outer layer comprisingan ethylene-vinyl acetate copolymer.
 6. A heat-shrinkable, biaxiallystretched multilayer film in accordance with claim 5 wherein said firstouter layer comprises an ethylene-vinyl acetate copolymer having a meltindex of from about 0.1 to about 1.0 decigram per minute, and a vinylacetate content of from about 9 to about 15 weight percent, based on theweight of said ethylene-vinyl acetate copolymer.
 7. A heat-shrinkable,biaxially stretched multilayer film in accordance with claim 5 whereinsaid ethylene-vinyl acetate copolymer comprising said first outer layeris selected from the group consisting of (a) a single ethylene-vinylacetate copolymer, and (b) a blend of ethylene-vinyl acetate copolymershaving melt indices of from about 0.1 to about 1.0 decigram per minute,and vinyl acetate contents of from about 9 to about 15 weight percent,based on the weight of said ethylene-vinyl acetate copolymers.
 8. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 5 wherein said second outer layer comprises an ethylene-vinylacetate copolymer having a melt index of from about 0.1 to about 1.0decigram per minute, and a vinyl acetate content of from about 3 toabout 18 weight percent, based on the weight of said ethylene-vinylacetate copolymer.
 9. A heat-shrinkable, biaxially stretched multilayerfilm in accordance with claim 5 wherein said core layer comprises avinylidene chloride-methyl acrylate copolymer containing at least about85 weight percent of vinylidene chloride, based on the weight of saidvinylidene chloride copolymer.
 10. A heat-shrinkable, biaxiallystretched multilayer film in a accordance with claim 5 wherein saidvinylidene chloride copolymer contains a maximum of 5 weight percentplasticizer, based on the total blend weight of additives and saidvinylidene chloride copolymer.
 11. A heat-shrinkable, biaxiallystretched multilayer film in accordance with claim 5 wherein said secondouter layer comprises a blend of at least two ethylene-vinyl acetatecopolymers, wherein one of said ethylene-vinyl acetate copolymers has amelt index of from about 0.1 to about 1.0 decigram per minute and avinyl acetate content of from about 10 to about 18 weight percent, basedon the weight of said copolymer, and one of said ehtylene-vinyl acetatecopolymers has a melt index of from about 0.1 to about 1.0 decigram perminute and a vinyl acetate content of from about 2 to about 10 weightpercent, based on the weight of said copolymer.
 12. A heat-shrinkable,biaxially stretched multilayer film in accordance with claim 11 whereinsaid blend of ethylene-vinyl acetate copolymers has a vinyl acetatecontent of from about 3 to about 18 weight percent, based on the weightof said blend of ethylene-vinyl acetate copolymers.
 13. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 5 wherein said first outer layer has a thickness from about 1.1mils to about 1.6 mils.
 14. A heat-shrinkable, biaxially stretchedmultilayer film in accordance with claim 5 wherein said core layer has athickness of from about 0.25 mil to about 0.45 mil.
 15. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 5 wherein said second outer layer has a thickness of from about0.4 mil to about 1.0 mil.
 16. A heat-shrinkable, biaxially stretchedmultilayer film in accordance with claim 5 wherein said film has a totalthickness of from about 1.75 mils to about 3.0 mils.
 17. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 5 wherein said film has been irradiated to a dosage level ofbetween about 2 megarads and about 3 megarads.
 18. A heat-shrinkable,biaxially stretched multilayer film in accordance with claim 1fabricated in the form of a bag.
 19. A heat-shrinkable, biaxiallystretched multilayer film suitable for packaging primal and sub-primalmeat cuts and processed meats, said film having a first outer layercomprising an ethylene-vinyl acetate copolymer having a melt index offrom about 0.1 to about 1.0 decigram per minute and a vinyl acetatecontent of from about 9 to about 15 weight percent, based on the weightof said ethylene-vinyl acetate copolymer, said ethylene-vinyl acetatecopolymer being selected from the group consisting of (a) a singleethylene-vinyl acetate copolymer, and (b) a blend of ethylene-vinylacetate copolymers having melt indices and vinyl acetate contents withinthe aforementioned ranges; a core layer comprising a vinylidenechloride-methyl acrylate copolymer containing from about 5 to about 15weight percent of methyl acrylate, based on the weight of saidvinylidene chloride copolymer; and a second outer layer comprising anethylene-vinyl acetate copolymer selected from the group consisting of(a) an ethylene-vinyl acetate copolymer having a melt index of fromabout 0.1 to about 1.0 decigram per minute and a vinyl acetate contentof from about 3 to about 18 weight percent, based on the weight of saidethylene-vinyl acetate copolymer, and (b) a blend of at least twoethylene-vinyl acetate copolymers, wherein one of said ethylene-vinylacetate copolymers has a melt index of from about 0.1 to about 1.0decigram per minute and a vinyl acetate content of from about 10 toabout 18 weight percent, based on the weight of said copolymer, and theother ethylene-vinyl acetate copolymer has a melt index of from about0.1 to about 1.0 decigram per minute and a vinyl acetate content of fromabout 2 to about 10 weight percent, based on the weight of saidcopolymer.
 20. A heat-shrinkable, biaxially stretched multilayer film inaccordance with claim 19 wherein said multilayer film has beenirradiated to a dosage level of between about 1 megared and about 5megarads.
 21. A heat-shrinkable, biaxially stretched multilayer film inaccordance with claim 20 wherein said vinylidene chloride-methylacrylate copolymer contains a maximum of 5 weight percent plasticizer,based on the total blend weight of additives and said vinylidenechloride-methyl acrylate copolymer.
 22. A heat-shrinkable, biaxiallystretched multilayer film in accordance with claim 20 wherein saidvinylidene chloride-methyl acrylate copolymer contains at least about 85weight percent of vinylidene chloride, based on the weight of saidvinylidene chloride copolymer.
 23. A heat-shrinkable, biaxiallystretched multilayer film in accordance with claim 20 wherein said firstouter layer has a thickness of from about 1.1 mils to about 1.6 mils.24. A heat-shrinkable, biaxially stretched multilayer film in accordancewith claim 20 wherein said core layer has a thickness of from about 0.25mil to about 0.45 mil.
 25. A heat-shrinkable, biaxially stretchedmultilayer film in accordance with claim 20 wherein said second outerlayer has a thickness of from about 0.4 mil to about 1.0 mil.
 26. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 20 wherein said film has a total thickness of from about 1.75 milsto about 3.0 mils.
 27. A heat-shrinkable, biaxially stretched multilayerfilm in accordance with claim 20 wherein said film has been irradiatedto a dosage level of between about 2 megarads and about 3 megarads. 28.A heat-shrinkable, biaxially stretched multilayer film in accordancewith claim 20 fabricated in the form of a bag.
 29. A bag suitable foruse in shrink packaging primal and sub-primal meat cuts and processedmeats, said bag comprising a biaxially stretched mulitlayer filmcontaining a barrier layer comprising a vinylidene chloride-methylacrylate copolymer containing from about 5 to about 15 weight percent ofmethyl acrylate, based on the weight of said vinylidene chloridecopolymer.
 30. A bag in accordance with claim 31 wherein said barrierlayer is a core layer.
 31. A bag in accordance with claim 31 whereinsaid multilayer film has at least three layers.
 32. A bag in accordancewith claim 31 wherein said multilayer film has been irradiated to adosage level of between about 1 megarad and about 5 megarads.
 33. A bagin accordance with claim 31 wherein said multilayer film comprises afirst outer layer comprising an ethylene-vinyl acetate copolymer, a corelayer comprising a vinylidene chloride-methyl acrylate copolymer, and asecond outer layer comprising an ethylene-vinyl acetate copolymer.
 34. Abag in accordance with claim 35 wherein said ethylene-vinyl acetatecopolymer comprising said first outer layer has a melt index of fromabout 0.1 to about 1.0 decigram per minute and a vinyl acetate contentof from about 9 to about 15 weight percent, based on the weight of saidethylene-vinyl acetate copolymer.
 35. A bag in accordance with claim 35wherein said ethylene-vinyl acetate copolymer comprising said firstouter layer is selected from the group consisting of (a) a singleethylene-vinyl acetate copolymer, and (b) a blend of ethylene-vinylacetate copolymers having melt indices of from about 0.1 to about 1.0decigram per minute and vinyl acetate contents of from about 9 to about15 weight percent, based on the weight of said ethylene-vinyl acetatecopolymer.
 36. A bag in accordance with claim 35 wherein said core layercomprises a vinylidene chloride-methyl acrylate copolymer containing atleast about 85 weight percent of vinylidene chloride, based on theweight of said vinylidene chloride-methyl acrylate copolymer.
 37. A bagin accordance with claim 38 wherein said vinylidene chloride copolymercontains a maximum of 5 weight percent plasticizer, based on the totalblend weight of additives and said vinylidene chloride copolymer.
 38. Abag in accordance with claim 35 wherein said second outer layercomprises an ethylene-vinyl acetate copolymer having a melt index offrom about 0.1 to about 1.0 decigram per minute and a vinyl acetatecontent of from about 3 to about 18 weight percent, based on the weightof said ethylene-vinyl acetate copolymer.
 39. A bag in accordance withclaim 35 wherein said second outer layer comprises a blend of at leasttwo ethylene-vinyl acetate copolymers, wherein one of saidethylene-vinyl acetate copolymers has a melt index of from about 0.1 toabout 1.0 decigram per minute and a vinyl acetate content of from about10 to about 18 weight percent, based on the weight of said copolymer,and one of said ethylene-vinyl acetate copolymers has a melt index offrom about 0.1 to about 1.0 decigram per minute and a vinyl acetatecontent of from about 2 to about 10 weight percent, based on the weightof said copolymer.
 40. A bag in accordance with claim 42 wherein saidblend of said ethylene-vinyl acetate copolymers has a vinyl acetatecontent of from about 3 to about 18 weight percent, based on the weightof said blend of ethylene-vinyl acetate copolymers.
 41. A bag inaccordance with claim 35 wherein said first outer layer has a thicknessfrom about 1.1 mils to about 1.6 mils.
 42. A bag in accordance withclaim 35 wherein said core layer has a thickness of from about 0.25 milto about 0.45 mil.
 43. A bag in accordance with claim 35 wherein saidsecond outer layer has a thickness of from about 0.4 mil to about 1.0mil.
 44. A bag in accordance with claim 35 wherein said film has a totalthickness of from about 1.75 mils to about 3.0 mils.
 45. A bag inaccordance with claim 35 wherein said film has been irradiated to adosage level of between about 2 megarads and about 3 megarads.
 46. A bagsuitable for use in shrink-packaging primal and sub-primal meast cutsand processed meats, said bag comprising a biaxially stretchedmultilayer film having a first outer layer comprising an ethylene-vinylacetate copolymer having a melt indexed of from about 0.1 to about 1.0decigram per minute and a vinyl acetate content of from about 9 to about15 weight percent, based on the weight of said ethylene-vinyl acetatecopolymer, said ethylene-vinyl acetate copolymer being selected from thegroup consisting of (a) a single ethylene-vinyl acetate copolymer, and(b) a blend of ethylene-vinyl acetate copolymers having melt indices andvinyl acetate contents within the aforementioned ranges; a core layercomprising a vinylidene chloride-methyl acrylate copolymer containingfrom about 5 to about 15 weight percent of methyl acrylate, based on theweight of said vinylidene chloride copolymer; and a second outer layercomprising an ethylene-vinyl acetate copolymer selected from the groupconsisting of (a) an ethylene-vinyl acetate copolymer having a meltindex of from about 0.1 to about 1.0 decigram per minute and a vinylacetate content of from about 3 to about 18 weight percent, based on theweight of said ethylene-vinyl acetate copolymer, and (b) a blend of atleast two ethylene-vinyl acetate copolymers, wherein one of saidethylene-vinyl acetate copolymers has a melt index of from about 0.1 toabout 1.0 decigram per minute and a vinyl acetate content of from about10 to about 18 weight percent, based on the weight of said copolymer,and the other ethylene-vinyl acetate copolymer has a melt index of fromabout 0.1 to about 1.0 decigram per minute and a vinyl acetate contentof from about 2 to about 10 weight percent, based on the weight of saidcopolymer.
 47. A bag in accordance with claim 46 wherein said vinylidenechloride-methyl acrylate copolymer contains at least about 85 weightpercent vinylidene chloride, based on the weight of said copolymer. 48.A bag in accordance with claim 46 wherein said multilayer film has beenirradiated to a dosage level of between about 1 megarad and about 5megarads.
 49. A bag in accordance with claim 46 wherein said vinylidenechloride-methyl acrylate copolymer contains a maximum of 5 weightpercent plasticizer, based on the total blend weight of additives andsaid vinylidene chloride-methyl acrylate copolymer.
 50. A bag inaccordance with claim 46 wherein said first outer layer has a thicknessof from about 1.1 mils to about 1.6 mils.
 51. A bag in accordance withclaim 46 wherein said core layer has a thickness of from about 0.25 milto about 0.45 mil.
 52. A bag in accordance with claim 49 wherein saidsecond outer layer has a thickness of from about 0.4 mil to about 1.0mil.
 53. A bag in accordance with claim 49 wherein said film has a totalthickness of from about 1.75 mils to about 3.0 mils.
 54. A bag inaccordance with claim 49 wherein said film has been irradiated to adosage level of between about 2 megarads and about 3 megarads.
 55. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 1 wherein said barrier layer comprises a vinyldene chloride-methylacrylate copolymer containing at least about 85 weight percent ofvinylidene chloride, based on the weight of said vinylidene chloridecopolymer.
 56. A heat-shrinkable, biaxially stretched mulitilayer filmin accordance with claim 1 wherein said vinylidene chloride copolymercontains a maximum of 5 weight percent plasticizer, based on the totalblend weight of additives and said vinylidene chloride copolymer.
 57. Aheat-shrinkable, biaxially stretched multilayer film in accordance withclaim 1 wherein said film has a total thickness of from about 1.75 milsto about 3.0 mils.
 58. A heat-shrinkable, biaxially stretched multilayerfilm in accordance with claim 1 wherein said film has been irradiated toa dosage level of between about 2 megarads and about 3 megarads.